Press with auxiliary cylinder circuit



Ana-185 P. POCOCK 2,293,357

PRESS WITH AUXILIARY CYLINDER CIRCUIT Original Filed June 7, 1938 37 7Attorney: 7

Patented Aug. 18, 1942 PRESS WITH AUXILIARY CYLINDER CIRCUIT Paul C.Pocoek, Marion, Ohio, assignor to The Hydraulic Development Corp.,

Inc., Wilmington, Del., a corporation of Delaware Original applicationJune 7, 1938, Serial No.

Divided and this application August 11, 1939, Serial No. 289,680

8 Claims. 01. 1o0- 71) This invention relates to presses, and inparticular, to arrangements for operating auxiliary rams in hydraulicpresses.

One object of this invention is to provide ahydraulic press operatingcircuit, wherein an independent pressure-operated device, such as anauxiliary ram, is actuated by pressure fluid generated in response tothe motion'of one ofthe' press plungers.

Another object is to provide such a circuit, wherein the auxiliarypiston is actuated by pressure fluid trapped on one side ofa'double-acting piston connected to the press mechanism.

Another object is to provide "such akcircuit, wherein anauxiliary'piston is hydraulically connected to one side of adouble-acting push-back piston so as to be operated by the fluidentrapped and compressed on one side 'of this double-acting push-backpiston.

This application is a division of my copending application, Serial No.212,327, filed June 7, 1938.

In the drawing:

Figurel is a side elevation, partly in section along the axes of thepush-backv and auxiliary rams, of a hydraulic press operating circuitwhich actuates an auxiliary ram from fluid entrapped on one side of a.double-actingpushback ram.

Figure 2 is an enlarged cross-sectional view of the valve of the presscircuit shown in Figure 1.

In general, the hydraulic press operating circuit of the presentinvention includes a main ram and push-back rams supplied with pressurefluid from a pump through, a four-way valve. The push-back rams aredouble-acting and one side of one crboth or the push-back rams isconnected to in auxiliary cylinder containing an auxiliary piston. Inthis manner, the auxiliary pistcn is actuated by pressure fluid supplicdand generated as the result of the motion of t e push-back rams incompressing the en- Referring to the drawing in detail, Figure 1 shows ahydraulic press having an auxiliary piston such as may be used formoving a die, ac-

tuated by pressure fluid generated as a result of the irappingof fluidon one side of a doubleacting piston, such as a push-backpiston. Inparticular, Figure 1 shows a hydraulic press having a bed 50, a head 5|interconnected by strain rcds 52, upon the ends of which are threadednuts 53, and a surge tank 54 mounted upon the head for supplying theworking fluid, such. as oil. by which the various circuits are actuated.

Within/the Press head 5| is a main cylinder 'interionof the surge tank54.

55 communicating through a port 58 with the Mounted in the port 56 is asurge check valve 51, of the type disclosed in the Ernst Patent No.1,956,758, of May 1, 1934, and forming no partof the present invention.This surge check valve 51 serves to preflll the main cylinder 55 as themain plunger 58 moves downwardly under the influence of gravity, andalso is forcibly opened by fluid reaching it from the push-back circuitduring the retraction stroke of the main plunger 58. The maincylinder,55,- within which the main plunger 58 reciprocates, is closedat its lower end by an annular packing 59, compressed by a gland 60 toprevent leakage therefrom around the main plunger 58. The latter isconnected to a platen 6|, reciprocable relatively to the strain rods 52and having a platen side arm 52 on either side thereof.

Connected to each lateral arm 62 is a pushback plunger 63 having apiston head 64 reciprocable within the push-back cylinder bore 65 withinthe push-back cylinder 66. The pushback cylinder bore 65 is closed by anannular cylinder head 51, with a packing 68 compressed by a gland 69 forthe prevention of leakage. The bottom of the push-back cylinder bore 65is provided with a port 10, from which a conduit ll leads to the T 12from which the conduits I3 and H lead to the push-back connection 15 ofthe reversible variable delivery pump 16. A branch conduit 11 leads to acheck valve 18 within the surge tank 54, The check valve 18 opensinwardly in the direction of the pump [6, but closes outwardly in thedirection of the surge tank 54.

- The pump I6 is also provided with a forward connection 19 having aconduit leading to the connection 8l, having a "port opening into themain cylinder 55 above the main plunger 58. Leading from the T 12 is aconduit 82 running around the press bed 50 to the bottom port of anotherpush-back cylinder (not shown) similar to the push-back cylinder 55. Thepump 16 is of the well-known reversible variable delivery type. withradial pistons and. cylinders, and having a servomotor 83 for shiftingthe flow-control member or shift ringot the pump under the control ofthe servomotor valve rod 84. On the opposite side of the pump is asafety centering device 85 for bringing the shift ring back to itscentral or no delivery position in the event .of stoppage of the drivingmotor, thereby preventing the coasting down of the main plunger underthe influence of its weight. The details lar I93 on the of theservomotor 93, servomotor control valve rod 34 and safety centeringdevice 35 are disclosed in' the copending application of Walter Ernst,Ser. No. 170,250, filed October 21, 1937, now matured into Patent No.2,184,665, dated December 26, 1939, and form no part of the presentinvention.

Pivotally connected to the outer end-of the valve rod 34 is a lever 35,pivoted as at 31 on the swingi link 93,- which in turn, is pivoted at99. Pivotally connected to the lever 99 is a connecting rod pivotallyconnected to one arm of the bellcrank 9|, to the opposite arm of whichis pivotally connected the connecting rod 92. The lower end of theconnecting rod to one arm of the bellcrank 93, to the opposite 99, theopposite end of which is 4 92 is pivotally connected arm of which ispivotally connected the connecting rod 94. The left-hand end of theconnectin rod 94 is pivotally connected to the bellcrank arm 95 of alever 95, which is pivotally mounted upon the Jack shaft 91. Pivotallyconnected to the right-hand end of the lever 95 is an armature rod 93,connected at its lower end to the armature 99 of the solenoid Ill. Theleft-hand end of the lever 93 is yoke-shaped, with rounded engaging anThe latter is reciprocably mounted in the bosses I94 and I95 extendingoutwardly from the press head 5i and bed 53. respectively.

Mounted upon the press head switch I99, forming a part of the electricalcircuit containing the solenoid I99 and actuated I91 upon the maincontrol rod I93. The latter likewise carries collars Ill and I99,surrounded by and adapted to be engaged by the arm extension IIIprojecting forwardly from the platen side arm 52. The engagement of thearm extension I59 with the colupward stroke of the platen 9i lifts themain control rod I93 to shift the servomotor control valve rod 94, andconsequently the pump shift ring, to their neutral positions for haltingthe upward motion of the platen 5|. On the other hand, the engagement ofthe arm extension III with the collar I99 on the downward stroke of theplaten 5|, operates the main control rod I93 in a downward direction toshift the servomotor control valve rod 84 to its reversed position,thereby moving the shift ring of the pump 19 to its reverse deliveryposition so as to cause the beginning of a retraction stroke of the'main plunger 5| by supplying pressure fluid through the conduits H, 13,and 14 leading to the push-back cylinders 59.

The main control rod I93, near its lower end, carries a pair of spacedcollars III engaging the rounded yoke ends II! of a lever am Hipivotally mounted on the jack shaft II4, which in turn. is'mounted uponthe bed 59 of the press. Secured to the lever arm H3 and forming, ineffect, the second arm of a bellcrank, is the hand lever II5. Bymanipulating this hand lever III in opposite directions, the maincontrol rod I" may be lifted or depressed to operate manually theservomotor control valve rod 34, thereby contlrolling the setting-of thevariable delivery pump II is a limit The arrangement according to Figure1 is adapted to actuate an auxiliary piston or ram for operating anysuitable device. For purposes of example, Figure 1 shows this device toconsist of a die holder II5, which is slidable to and holders or slidingrod II1 having a crosshead II9 thereon, the lower end of which slides ing'uideways I I9. The die holder H5 is suitable for carrying a die of anydesired form so as to move the die into and out of position beneath theplaten 5|. Such die tables II5 are known to those skilled in the art, aswell as the various kinds of dies utilized therewith, depending upon thenature of the workpiece. Accordingly, the details thereof form no partof the present invention, and a disclosure of a conventional form willbe found in the patent to Ernst No. 2,009,487, dated July 30, 1935. Forso moving the die holder lit the connecting rod II1 isthreaded at itsouter end I29 to carry a pair of nuts I2I, between which is secured ayoke I22, the lower end of which is secured between the nuts I23threaded on the outer end I24 of the auxiliary piston rod I25. Thelatter carries a piston head I25, reciprocable within the cylinder boreI21 of the auxiliary cylinder I23, the latter being carried by thebracket I29, which also supports the guideways III and is in turnsecured to the side of the press bed 53.

The auxiliary cylinder I23 is closed by an annular cylindrical head I39,having a packing I3I compressed by a gland I32 to prevent leakage. Theright-hand end of the auxiliary cylinder I23 is provided with a port I33having connected thereto a conduit I34 leading to the T I35 upon theconduit 13, and communicating with the latter. The auxiliary cylinderI29 at its opposite end is provided with a port I35, to which isconnected the conduit I31 leading to the port I33 in the push-backcylinder 55 above the uppermost position of the piston head 54.

Leading from the port I39 and connected to the conduit I31 is a conduitI39, leading to the 5|. The auxiliary valve control rod I41 passes'outwardly from the casing I42, through the annular casing head I5I. Thelower end of the valve member I44 terminates in the reduced diametervalve rod extension I52, leading downwardly through the spring casingI53, secured to the valve casing I42, and into the socket I54. Thespring casing I53 contains a spring chamber I55 inclosing a coil springI56, surrounding the valve rod extension I52 and engaging a collar I51slidably mounted on the valve rod extension I52. When the valve memberI44 is moved downwardly a suiiicient distance, the annular shoulder I53between the valve member I44 and the valve rod extension I52, engagesthe collar I51, pushing the latter downwardly and compressing the coilspring I59. The valve casing I42 is provided with a passageway I59,leading to spaced ports I and I 6| opening into the annular enlargementsI52 and I53 of the valve bore I43. Opening into the passageway I59 is aport I54, to which is connected the conduit I95 leading upwardly to theinterior of the surge tank 54.

In the operation of the circuit shown in Figure 1, the pump servomotorcontrol valve 34 is shifted either manually..by moving the hand leverH5, or electrically by energizing the solenoid I99 fro across the bed 59by means of a connecting so as to place the pump shift ring m forward lV 2,293,357 delivery position. this position the. pump 1a deliverspressure fluid through the connection 19 to the conduit 80, and throughthe connection BI into the main cylinder 55above the main plunger58. Thelatter moves downwardly, aided by gravity, and the space itleaves isprefllled by means of the automatically opening surge check valve 51.Fluid thereby passes through the port 56, from the surge tank 54," intothe topof the main cylinder 55., The descent of the main plunger 58, andthe consequent descent of the platen 6I, causes the "descent of thepush-back plungers 63 and their piston heads 164 within the cylinderbores 65 or the push-back cylinders 56.,

The fluid beneath the push-back piston heads 64 is discharged through,the ports 10 and the conduits H and 02,, into the conduits 13 andj14,and thence into. the push-back connection 15, now constituting thesuction side of the pump".

As the push-back piston heads 64 are moved downwardly, the suctioncreated above them draws fluid into the tops of the push-back cylinderbores 65, through the conduit I39, the still open auxiliary controlvalve HI and the conduit I65 leading to the latter from the interior ofthe surge tank 54. ,Thev'alve heads I45and I46 remain in theirraisedpositions, shown in Figure 1, even after theplaten arm I50 hasdisengaged itself from the collar I49 because of thefriction of thepacking surrounding the auxiliary valve control rod I41 beneath thevalve casing head II. As the platen 6| and main'plunger 50.near'the iend of their. downwardstrokes, the platenarm any motion of thedie holderII6is brought about. When the auxiliary control valve I4I closes uponthe-coilxspring I56 andsliding collar I61 engage the annular shoulderI58 and push the valve member I44 and the auxiliaryvalve control rod I41upwardly until the collar I51 engages the. top of the springchamberjl55, and temporarily halts the upward movement of the valvemember I44. At this point the valveheads I45 and I46 come to restbetween the ports I60 and I6I,shutting these off from communication withthe' p'ort I40 and hence closing the valve I4I initsmid-position. 'The'reason for allowing the platen 6| to move upwardly a short distancebefore closing the auxiliary control valve III is to insure that the dieupon the die holder H6 is relieved of the pressure of the platen beforein this manner, the fluid is trapped in the line I39 and hence cannotany longer be discharged through the valve I and. conduit I65,'into thesurge tank 54. Accordingly, this fluid trapped above the upwardly movingpush-back piston head 64 passes downwardly through the conduit "I31;into the left-hand end of the cylinder bore the-line 14 at that. time isstanding in the I50 engages the lowercollar I46 upon theauxiliarycontrol rod I 41, andpushes the valve member I44 and the valve heads I45and I46 downwardly through the closed position of the auxil-, ,iary;control valve I H, into asecondopenposition thereof. Meanwhile, the 1annular shoulder I56 has engaged thesliding collar I51 and compressedthev coil spring- I56. Infthis, the lowermost position ofthevalve I4I, the port I isin traction or push-back stroke, the: platen armI50:engagesthecollar I40 and moves the auxilcommunication with the portsI6I; and I64 across the valve bore I43, becausetheval epIston head I46has descended beneath the port I6I. Thus,

the valve MI in its lowermost position still permits fluid to passfreely betweenthe conduits I3! and I65.

The pump andpresslcontrol system are then reversed in any suitable way,either manually by the operation of the hand lever H5, or Lauto-,matically by apressure-responsive,switch I10 operated bythe hydrauliomotor I1I on the press head5I or position-responsive :switch I12 on thebracket I13 and engageable bythe platen arm I 62, ineither casedeenergizing the solenoid I00. This causes the shifting of the maincontrol rod I03and the servomotor value "control rod 64, with the.result that the servomotor 63moves the shift ring or flow-controlmember of the pump 16 over to its reversed position: In this positionthe connections" and 15 become, respectively, the suction and pressureconnections of thepump 16. Fluidis therefore drawn from the maincylinder 55 above the main plunger 50, through the 1 connection 81,conduit 00*"and pump connection 19, into the" pump 16, fromwhence it isdischarged as "pressure' fluid through the connection I21, causing thedie-moving piston I26 with its yoke I22, connecting rod H1 and dieholder II6, to move to the right into the retracted position thereof,out from beneath the'central position thereof. The effective area of thepiston head I 26 is, of course, only equal to the area of the piston rodI25 because push-back pressure from right-hand 'end of the auxiliarycylinder' bore I21 because of the connection of the conduit I34bthereto.1 V v -When the platen 6Inears the top of its reiary cylinder bore I21,through the port l and .conduit I34 from the conduit 13, to.-push theauxiliary pistonhead I26 to the left and move the die holder II6 backinto its working position centrally beneath the platen 6I. Meanwhile,the

I platen arm extension IIO of the platen arm 62 has engaged the collarI08 upon the main control rod I03 and shifted the servo-motor controlvalve rod 64 to its neutral position, thereby moving the shift ring ofthe pump 16 to its neutral delivery position and halting the upwardtravel of the main plunger 58 and platen 6I.

The foregoing illustration in the embodiment shown inFigure 1 merelyshows the operation *0! a die carrier by means of fluid supplied from ione of the push-back cylinders. It will be seen,

15; the conduits 14; 16 and H andwflginto the push-backbylinder bores 65beneath the push back piston heads Sly-causing the latter to moveupwardly.

and. after it has moved a short distance, the

"platen arm I50 disengages thepcollar I48, where consequently movesupwardly,

however, that this arrangement is adapted. to operate other devices thandie holders, the latter being shown merely as an. example. In ahydraulicpress it is frequently advantageous to incorporate such apressure-actuated device for performing some independent function, suchas indexing amovable die holder; as shown in Fig "ure 1, or for removingor feeding workpieccs, etc.

Motions of this nature must always be accurately timed with themovements of themain ram, and

follow in proper sequencetherewith. Ordinarily, however, where twopressure-actuated pistons are located inseparate cylinders, eachperforming a different work but open to the same pressure source, thereis no certainty that both pistons will move in a desired sequence. Onepiston may move before the other, both may move together, or one maymove part way and then the other, depending upon the resistanceencountered as compared to the respective areas of these pistons. V

In the present invention, however, the pistons must operate in theproper sequence because the pressure fluid for actuating the secondpiston is obtained directly as a result of the movement of the firstpiston. Thus, the fluid trapped upon one side of the double-acting presspiston is conducted to the auxiliary piston to cause its operation inprecisely the predetermined sequence, and without any possibility ofdeviation from this sequence.

It will be understood that I desire to comprehend within my inventionsuch modifications as plunger, hydraulic means for moving said secondaryplunger and said auxiliary motor, means for discharging fluid from themotor-connected side of said secondary plunger selectively to said motoror to an exhaust, valve means disposed between said secondary plungerand said discharging means for controlling communication between saidplunger and said discharging means, and control means adapted inresponse to the motion of said secondary plunger to close said valvemeans to cause said secondary plunger to create and convey fluidpressure, to said auxiliary motor for operating the same in onedirection, said control means also being adapted to open said valve forestablishing communication between said motor connected side of saidsecondary/plunger and said exhaust to cause said hydraulic means tooperate said auxiliary motor in the opposite direction.

2. In ahydraulic press circuit, a main plunger, a double-actingsecondary plunger operatively connected with said main plunger, anauxiliary double acting piston having one side hydraulically connectedto one side of said secondary plunger and the other side hydraulicallyconnected to a pressure fluid source, means for discharging fluid fromthe motor-connected side or said double acting piston, valve meansdisposed between said double-acting piston and said discharging means,means movableconcomitantly with the movement of said double actingpiston for closing said valve means to cause said piston to create andconvey fluid pressure in response to its movement to ,said auxiliarymotor for operating the same. a

3. In a hydraulic press circuit, a main plunger, a double actingpush-back plunger connected thereto, an auxiliary. hydraulic plunger, a

hydraulic circuit interconnecting both sides of said push-back plungerwith said auxiliary hydraulic plunger, a source of pressure fluid forselectively supplying pressure fluid to said main back plunger, andmeans responsive to a pre determined motion of one of said plungers forcausing said control means to entrap said pressure fluid, whereby thispressure fluid is caused to pass to said auxiliary plunger for operatingthe same after the push-back plunger has moved a predetermined distance.

4. In a hydraulic press circuit, a main plunger, a double actingpush-back plunger connected thereto, an auxiliary hydraulic plunger, ahydraulic circuit continuously interconnecting both sides of saidpush-back plunger with opposite sides of said auxiliary hydraulicplunger, valve means for conveying fluid from one side of said push-backplunger selectively to one side of said auxiliary plunger or to anexhaust, a fluid source for selectively supplying pressure fluid to saidmain plunger onto said push-back plunger, means responsive to apredetermined position of one of said plungers during the return strokeof said main plunger for causing said valve means to direct pressurefluid from said one side of said push-back plunger to said auxiliaryplunger for causing said auxiliary plunger to perform a stroke in onedirection, and means responsive to another predetermined position of oneof said plungers during the return stroke of said main plunger forcausing said auxiliary plunger to return to its previous position.

5. In a hydraulic press circuit, a main plunger, 9. double actingsecondary plunger operatively connected with said main plunger. a fluidsource for supplying pressure fluid selectively to said main or saidsecondary plunger, an auxiliary double acting piston having its oppositesides connected respectively to said secondary plunger and said fluidsource, and means responsive to the movement of said main plunger forcontrolling hydraulic connection between said secondary plunger and saidauxiliary piston, and between the latter and said fluid source topositively move said auxiliary plunger in two opposite directions, whilesaid main plunger moves in one and the same direction.

6. In a hydraulic press circuit, a main plunger, a double acting pushback plunger operatively connected with said main plunger, a source ofpressure fluid for selectively supplying pressure fluid to said mainplunger or to said push back plunger for respectively advancing orretracting said main plunger, an auxiliary plunger hydraulicallyconnected with both sides of said push back plunger, and meansresponsive to the travel of said main plunger during the movementthereof in one and the same direction for sequentially causing 'fluidexpelled by one side of said push back plunger to move said auxiliaryplunger in one direction, and pressure conveyed by the pump to theopposite side of said push back, plunger to move said auxiliary plungerin the opposite direction. r

7. In a. hydraulic press circuit, a main plunger, a push-back plungerconnected thereto, an auxiliary hydraulically operable piston, conduitmeans hydraulically interconnecting said pushback plunger with saidpiston, valve means having two spaced open end positions for releasingfluid from one side of said push-back plunger to an exhaust, and alsohaving an intermediate closed position for preventing fluid to escapefrom said one side of said push-back plunger to said exhaust, a fluidsource for supplying pressure fluid selectively to the main plunger orto the opposite side of said push-back plunger, and control meansresponsive to a predetermined motion oi one of said plungers for movingsaid valve means from one of its open end positions into itsintermediate closed position to entrap, the pressure fluid between saidfirst mentioned side of said push-back plungerand said valve means,whereby this pressure is caused tcpass to said auxiliary piston foroperating the same in response to the travel of one oi. said plungers inone direction.

8. In a hydraulic circuit amain plunger, a

' push-back plunger operatively connected to said main plunger andhaving a first area and an op.-

posed second area, a fluid source for supplying pressure fluidselectively to said mainplunger or i to said first area oi saidpush-back plunger for reciprocating said main plunger, a fluid operablef 5 ing hydraulic communication between said second areas, valve meanshaving two spaced open end positions-"for establishing hydraulicconnecpiston with a first area and an opposedgreater I second area,conduit means ior hydraulically intion between the'second area oi saidpush-back piungerand an exhaust, and alsohaving an intermediateclosedposition {or entrapping fluid between said second areas, andcontrol means operatively connected with one oi said plungers andresponsive to the supply of pressure fluid to the first area of saidpush-back plunger and the movement of the latter caused by said fluid tofirst move said valve means from one open end position into saidintermediate position, to cause fluid entrapped between said secondareas to move said piston from a first position into a second position,and thereafter to shift said valve means from said intermediate positionto the other end position to cause said piston to return to said firstposition.

terconnecting said first areas and for establish- PAUL c. rooocr;

